Inside of 40 years, from World War I to the Korean conflict, pilots went from shooting at each other with pistols from propeller-driven biplanes to dueling with cannons and missiles in jet aircraft moving faster than sound.

By Korea, “air breathers,” or jets, had replaced the finely crafted propeller-driven fighters of lore, and aerial duels between American F‑86 Sabres and Soviet-built MiG‑15s were fleeting visual encounters where the biggest challenge was to get close enough to fire.

As details began emerging hours after the incident, it appeared that President Obama was never in any danger because air-traffic controllers and the pilot of the Marine Corps helicopter carrying him and his party could see the propeller-driven Cessna clearly in the region's sunny skies.